Vehicle tire-pressure indicator



Aug. 12, 1930. H. JAcoBY VEHICLE TIRE PRESSURE INDICATOR v Filed Jan. 25. 1927 Patented Aug. 12, 1930 UNITED STATES PATENT OFFICE VEHICLE TIRE-PRESSURE INDCATOR Application filed January 25, 1927, Serial No. 163,547, and inA Germany January 26, 1926.

My invention relates to an electrical system in which a decrease in the air pressure of vehicle tires is indicated on the dashboard of the vehicle.

l attain these objects by means of the system illustrated in the accompanying drawing.

The invention consists of two physically independent electrical circuits, the only connection between the several circuits being the occasional ei'lect of the electromagnetic field,

produced by one part oi' one circuit, upon a part of the second circuit, one of said circuits being mounted on the Wheel of the vehicle, the

other circuit being mounted on the chassis pf the vehicle.

. The circuit which is mounted on the Wheel of the vehicle includes an electromagnet, a

battery or an inductor, and a circuit closing.

A pneumatic tire which consists of an outer casing c and an inner tube b are mounted on l rim d which latter is attached to the wheel i'elly l1. Tubular member g is positioned to extend radially of the wheel, through the telly 11. The outer end of the tubular member g is aflixed in air-tight relation to the inner tube b. Slidably mounted within the tubular member g there is placed a slide member h. which has a disc 2 affixed at the outer 40 end thereof. The portion member h which lies within tubular member g is somewhat reduced in diameter, as at 15, to provide an annular space, in which the coil spring z' is disposed. Coil spring is arranged to normally force the .slidel member h to protrude a short distance from the end of the tubular member Ai] the inner `end of the tubular member g and within the same there is mounted a contact collar 4 towhich there isattached spring contact fingers 10-10. Collar 4 is insulated from the tubular member g by means of insulating washers 6 and. 7. At the side of tubular member g and insulated therefrom there extends screw 17, which is insulated from and mounted in the collar 8 and contacts at its inner end with the contact collar 4.

The end 9 of the reduced portion 15 of slide member L is normally out of contact with contact ngers 10-10. However, the slide member h may be pressed inwardly against the action of spring z' until the end 9 contacts with spring contact fin ers 1010.

The Wheel structure a so carries an electro-` magnet r and a dry battery or an inductor g which are connected by circuit p-p to the tire circuit closer explained above.

On the frame of the vehicle there is mounted 'an armature s which operates to close contacts Z when it is attracted bythe electromagnet 1. The contacts Z control a signal circuit- :vwhich includes signal lamp a and battery y. The signal lamp a may be mounted in any position in which it may be conveniently observed by the operator of the vehicle, as for instance, on the dashboard of the vehicle.

The magnet 7' and armature s are positioned with respect to each other as to be immediately adjacent each other when the circuit closer device g-L is in vertical alignment between the earth and the axle of the wheel.

The operation of the device is as follows: lVhen the tire c becomes sott due to a leakage of the air therefrom, it will assume the position as shown in the' dotted lines, when in contact with the earth. As the softness increases the inner tube l will gradually reach a position so as to press the slide member as at 12, and move member k upward.

lVhen the slide member L is pressedupward a contact is established between 9 and 10--10 and a current flows through the following circuit: from one terminal of the battery or inductor g to electro-magnet 7', thencel through circuit p to'screw 17, contact lingers 10-10, across to tip 9 of member 15, and thence through the body of the circuit closer, collar 8, circuit p and back to thesecond terminal of the battery or' inductor. `Electro magnet r is accordingly energized and the magnetic iiurr of the magnet attracts armature s and closes contacts at which time a circuit is established through the signal light as follows: from one terminal ot" the battery y to signal lamp a through the oircuit X to armature s, contacts Z and hack through circuit to the other terminal of battery y, whereupon the light is illuminated and an indication is given of the deflation of the vehicle tire.

l have thus provided a simple and etiicient device of the kind described and for the purposes specified.

' lt is obvious that minor changes may be made in the form and construction of the invention Without departing from the spirit thereof. ltis not therefore desired to conne the invention to the exact form herein shown and described but it is desired to include all such changes as come Within the scope claimed.

Havincr thus described the invention, What is claimed as new, is:

In a system for signaling the deiation of a pneumatic tire on a Wheeled vehicle, a Wheel carried circuit including circuit closing means responsive to tire deiation, a source of current and an electromagnet, a rame carried circuit including a current responsive signal, a, source of current and a circuit closer, the movable element of said circuit closer being an armature for said magnet,

' means mounting said armature adjacent the Wheel and at a distance from the axis of the Wheel which is equal to the distance the magnet is from said axis whereby when the tires deiiation switch is closed the magnet is energized, the armature is attracted and the signal circuit close HERMANN JACBY. 

